Hi,
On your Cumulus configuration page (menu Configuration --> internet --> Site/Options tab)
you have a Web Site section where you have to indicate your host name (ie. ftp.mysite.com)
So, in optional file (Files tab) you have to include your "Internal" path only,
on many provider, this is kind of: public_html/weather or www/weather
(supposed that your site is in a "weather" folder).
Regards,
Jacques